Conventionally, various systems have been proposed for enabling persons at far distances to directly communicate with each other.
Among such systems, wire telephones, radio communications and mobile communications have been used most widely. In the wire telephones, it is possible to carry out communications using a plurality of telephones connected to exchanges with wire. In the radio communications, it is possible to carry out communications based on a direct transmission and reception of signals among a plurality of radio devices. In the mobile communications, it is possible to carry out communications using mobile communication terminals like portable telephones and PHSs (Personal Handy Phone) that are connected to exchanges by radio. These systems are common in that they are communication means based on voice, and that the communication parties are limited.
Further, as new communication systems distributed along the development of Internet technology in recent years, there are the electronic bulletin board system and the chat system. These are the systems in which a plurality of persons can interactively write and read sentences on Web pages stored in a server device using client devices connected to the server device via the Internet. Particularly, in the case of the chat system, the sentence display screen is updated in a relatively short time. Therefore, this has a certain level of real-time nature, and is excellent as a virtual interactive space. This chat system is different from the above mobile communication system and others in that generally the chat system is communication means based on characters, and that the dialogue is carried out between an unspecified number of the general public. The other party of the dialogue is not necessarily specified.
These conventional systems further have the following characteristics.
First, a plurality of persons can carry out mutual communications in the meeting telephone as a kind of a wire telephone, the radio communication, and the chat. For example, in the meeting telephone and the radio communications, a plurality of persons can mutually listen to their speeches. In the chat, a plurality of persons can write or look at the contents substantially at the same time.
Further, in the radio communications and the mobile communications, persons can communicate with each other while moving. In other words, in the radio communications, users can carry out conversations while walking or moving in a car or the like within a range in which it is possible to transmit/receive waves between radio devices. In the mobile communications, users can also carry out conversations while moving, within a range in which it is possible to transmit/receive waves between mobile communication terminals and the exchange.
Further, in the case of a car navigation system in which it is possible to read map information or the like in a mobile unit like an automobile, though this is not communications between persons, it is possible to present various kinds of information to the moving persons.
In the actual communications, there are many cases where a plurality of persons carry out conversations while moving. For example, such conversations are carried out between friends while they are walking in the town, or when family members are driving in one automobile. Through such communications, it is possible to spend the moving time more pleasantly and meaningfully.
However, among the conventional systems, only the radio communication system enables a plurality of persons to carry out communications while moving. Other systems cannot satisfy this requirement. Further, in the radio communication system, there is a limit to a range in which radio waves can reach. Therefore, when the moving range is wide, it becomes impossible to carry out communications.
In the case of carry out conversations while moving, more interesting communications can be achieved when it is possible to change the contents of the communications according to the current position of the user. For example, when it is possible to talk on various background scenes that change along the move, or when it is possible to obtain detailed knowledge from persons familiar with these places, the communications become more interesting.
However, of the conventional systems, only the car navigation system provides information of different contents according to the position of the user. Other systems cannot satisfy this requirement. However, the car navigation system is not the communication means between persons as described above, and it is impossible to achieve bidirectional communications.
There have also been proposed conventional systems that relate a position of a dialogue party to the contents of communications.
For example, according to Japanese Patent Application Laid-Open No. 9-23275, when a user itself has moved in a virtual space, and when that movement is small or when fields of vision are superimposed, voices of both parties are connected to the same voice mixer. Thus, the voice that each user can listen to changes according to the position of the user. Further, according to Japanese Patent Application Laid-Open No. 5-113941, a weight is placed on a reach range of a message of a user within a virtual space, and the weighted message is transmitted. Thus, a reach range of a message changes for each message.
However, these systems are for users who are virtually set in a virtual space to carry out communications. These systems do not assume the move of real persons in a real space. For example, these systems are structured based on the assumption that a user inputs a position of a self into the system. However, in reality, it is impossible for a user moving in the town to sequentially input the position of the self. Therefore, it is not possible to directly use these systems for communications in the real world.
Further, these systems are structured such that communications can be established within a constant range around a virtual position of the user. However, this can become an inconvenience. For example, according to these conventional systems, when two users A and B are in the same area C, they can have a dialogue when the distance between them is short, but they cannot have a dialogue when the distance is long. However, in the case of having a dialogue on the area C, for example, it is convenient when the dialogue is established so long as they are within the area C, regardless of a distance between the two persons. In other words, it is preferable to be able to establish communications within a range divided based on other concept than the positions of the users.
From the above, the conventional systems have still many problems as systems that change the contents of communication according to the current position of the user.
In recent years, there has also been an increasing requirement for achieving communications among an unspecified number of the general public. For example, when it is possible to frankly talk to various people walking around while walking in the town, it is possible to obtain information by accident that has not been known or to meet persons who have not been known by chance. Such accidental occurrence in communications cannot be obtained in the above conventional communication systems at all. In the mean time, this is a most interesting element for the user.
However, among the above conventional systems, only the chat system can provide accidental communications with an unspecified number of the general public. Other systems cannot satisfy this new requirement.